1. Field of the Invention
The present invention relates to a semiconductor storage apparatus including a plurality of pump circuits.
2. Background Art
In a semiconductor storage apparatus such as, for example, a NOR flash memory formed of an EEPROM, a voltage higher than the power supply voltage is needed when writing data into memory cells or erasing data from memory cells.
In such a semiconductor storage apparatus which needs the high voltage, a pump circuit is included and the needed high voltage is generated by boosting the power supply voltage in the pump circuit.
Some conventional semiconductor storage apparatuses include, for example, a standby pump circuit which operates according to an output voltage at the time of standby operation and an active pump circuit which operates according to the output voltage at the time of active operation (see, for example, JP-A 2000-105998 (KOKAI), JP-A 2000-268575 (KOKAI), and JP-A 07-85678 (KOKAI)).